Plaster composition.



UNITED STATES PATENT OFFICE.

MILTON T. J. OOHS, OF ALLENTOWN, PENNSYLVANIA.

PLASTER COMPOSITION.

SPECIFICATION forming part of Letters Patent No. 705,5Q2, dated. July22, 1902. Application filed September 28, 1901- Ser'ial No. 76,888.Specimens.)

To all whom, it may concern.-

Beit known that I, MILTON T.J.Oons, a citizen of the United States, anda resident of Allentown, in the county of Lehigh and State ofPennsylvania, have invented a new and Improved Plaster Composition, ofwhich the following is a full, clear, and exact description.

My invention relates to a plaster composition, more particularly for usein ordinary house-plastering on the inside or upon any ordinary surfaceused in building, although it can also be used outside with the bestresults.

One of the essential features of my invention is the mixture of a baseof hydraulic cement and a dope containing water for setting the samethatis to say, I have discovered that hydraulic cement when hardened in airby means of an absorbent substance containing water and used as aplaster instead of a cement or mortar has superior qualities. Theordinary plasters used in buildings are of various kinds; but in all ofthe best plasters now used the principal ingredient is plasterof-paris.It is found, however, that such plasters when used in the ordinary wayin connection with brickwork present so-called hard working qualities.None of said plasters are essentially hydraulic in their action.

I take silicate of aluminium-that is, ordinary clay-preferably of a goodquality and reduce it to powder. I also take chalk and reduce it to apowder. By mixing these two substances in their powdered form I make avery effective dope, which will hold large quantities of Water byabsorption. I use these materials in their raw state, their functionbeing merely that of an absorbent. I now take hydraulic cement of anyapproved kind, reduce it to a powdered form, and in its unslaked orquick state mix it with the ingredients above mentioned. These threeingredients thus mixed constitute my plaster.

It is found that the plaster is easily Worked and can be easily made tocohere to almost any substance. It does not split or crack, and itavoids many objections heretofore encountered in plaster. The water usedin slaking the cement is self-contained in the mixture, and it willharden aseifectually as hydraulic cement will harden under water.

My plaster is handled like other plastersthat is to say, when mixing upfor use certain proportions of sharp sand are added to the plaster,varying in quantity with the sharpness of the sand and the purpose forwhich it is to be used.

My plaster has practical working qualities which high-grade cements,such as Portland cement, do not possess. It will be seen, therefore,that I have produced a plaster suitable for houses and possessing manyof the qualities of hydraulic cement, but slightly weaker than the same,and yet which is essentially a plaster like any other plaster andpossesses working properties necessary in all good plasters.

Among the silicates of aluminium which may be used the best qualitiesare somewhat expensive. Kaolin, however, is comparatively cheap and maybe used to considerable advantage.

I find that my plaster mixture can be applied to lathwork with the bestresults.

It should be noted that the silicate of aluminium and the chalk are notto be burned in with the cement, but are made up in the raw state andadded to the cement after the latter is burned.

It may be noted that silicate of aluminium in the form of clay is notallowed to be used in either lime or cement mortars. Nevertheless I usethem to great advantage in my plaster, for the reason that there is awide difference between the strength required for mortars and forplasters. I have produced a composition which is harder and strongerthan ordinary plaster and which will work like a plaster, but which isinferior in strength to hydraulic cement. The silicate of aluminium orthe carbonate of lime may be used independently or may be mixed togetherto form the dope. I find that either of them makes a very good dope, butthat a mixture of the two is better. Any desired proportions may beused, depending largely upon the purity and quality of the material. Mypreferred proportions, by weight, however, are as follows: hydrauliccement, (say Port- ICO land cement,) two parts; silicate of aluminium,(say kaolin,) one part; carbonate of lime, (say chalk,) one part; watersufficient to saturate the last-mentioned ingredients.

Having thus described my invention, I claim as new and desire to secureby Letters Patent 1. A plaster, comprising hydraulic cement two parts,powdered silicate ofaluminiu m one part and powdered carbonate of limeone part, all of the said substances being admixed together.

2. A plaster, comprising powdered hydraulic cement two parts, powderedsilicate MILTON T. J. OCHS.

WVitnesses:

MILTON C. HENNINGER, R. L. SCHI'FFERT.

